Schaft



Patented Mar. 17, 1931 UNITED STATES PATENT, OFFICE enons SQHEUING AND Bauno WALA CH, or manna-1NoiiLnE MpnTrirn-Rnmn, enn- MANY, assronons 'ro rnn FIRM or o. H. nOEHR NGER sonn axrrnnensnrn scream, or NIEDER-INGELHEIM-ON-THE-RHINE, GERMANY, A CORPORATION or GERMANY rnoonss or MANUFACTURING 1,2,4-TnIAzoLEs No Drawing. Application filed October a, 192%}, Serial no. 403,112, and in Germany April 7, 1928.

The known process for preparing triazgoles from hydrazidine and acidanhydrid'es (see, for example, Richter, Lehrbuch deranorganischen Chemie, 1913, Vol. II, page 817) has the disadvantage that the hydrazidines, particularly the aliphatic hydrazidines, are only obtainable with great difficultyand are also very unstable, so that this method of preparation has found no practical application.

According to this invention, 1,2,4L-triazoles may be readily obtained by causing acyl hydrazines to react yvith imido compounds or With substances, which, under the conditions of the reaction, yield imido compounds, which may, on occasion, be unstable intermediate products incapable of being isolated.

In the said imido compounds of the type R and R represent any radicals, for example carbon-contannng radicals, WlllCll may also be connected together in a mug formation, Whilst X represents any radical which is capable of mutually reacting With one of the hydrogen atoms of the acylhydraZ1nei. e. another group or acyla'ted hydroxyl group, a halogen or the like.

Imido compounds of the aforementioned kind, such as imido esters oft he type Rrfi-OAU v NR2 or imido halogenides of the type Bri l-'01 and the like, may for example, be obtained as intermediate products from esters oi oximes by. intramolecular conversion, for example according to the equation genides, for example aci'd' chlorides, which bring about a" Beckmann transformation of the group whereby probably estel l ike compounds of the o Ximes, or esters of the enolic form of the corresponding acid amides of the above type are intermediately formed. I

Compounds 0t this type may also be obtained byacylating mono-substituted acid amides, the latter reacting in their enolic form.

Triazoles are therefore in general obtained, for exaniple,[bytreating oxime esters, for example the benzene sulphonic acid esters ofthe oXimes, With acyl hydrazines under conditions under which the esters undergo Beckmann transformation to the imido ester of the correspondingsecondary acid amide. Further, triazoles may also be obtained by subjecting oXimes to the Beckmann transformation with the aid of acid halogenides, such as phosphorus pentachl'oride, phosphorus oxychlo "ide and the like and by causing acyl hydrazines to react with the reaction product. The same imido compounds and therefore also the triazoles may be obtained from mono-substituted acid amides by a'cylating the same in their onolic form, for example by treating the mono-substituted acid amides with acid halogenides, such as acid chlorides, and then causing anacyl hydrazine to react With the reaction product.

The reaction takes place according to the following equations The residue X of the imido compound is first eliminated with a hydrogen atom of the primary amino group of the acyl hydrazine and then the 1,2,4-triazole is formed by the elimination of Water from the resulting primary hydrazidine.

Depending on the nature of the starting materials employed, the triazole is spontaneously formed under the conditions of the reaction by the elimination of water or the acyl hydrazine, which may, on occasion, be capable of being isolated, is converted into the triazole by heating.

The reaction components may be caused to react with one another in solution or in sus ension or in certain cases even without the use of solvents or dispersing agents. T he reaction components may be employed in molccilar proportions, or, if desired, an excess of one of the components, for exam ale the acyl hydrazine, may be employed. The conversion is preferably effected in the presence of an inert organic solvent, such as chloroform, benzen alcohol or the like, or of mixture of solvents, water, on occasion, being also present.

The temperatures employed for the conversion may vary within wide limits, depending on the nature of the substances present. The operation may be effected both at comparatively low temperature ranges, for example those as low as 10 6., or also at ordinary or at increased temperature, under certain circumstances even at temperatures far above 100 C.

In many cases, for example when employing the reaction components in the form of emulsions, it is advisable to promote the proccos of the reaction in a desired manner or to accelerate the same by the use of suitable, if necessary powerful, stirring; apparatus.

The sequence, in. which the reaction components are cause to react upon one another, may vary according to the conditions. Thus, for example, starting with oxime esters, the lleckmann transformation may be etii'ected under suitable temperature conditions after the introduction of the acyl hydrazine.

On treating oximes or nMme-substituted acid amides with acid haloaenides, such as phosphorus oxychloride, phosphorus pentachloride, benzene sulphonic chloride, thionyl chloride and the like, the operation is in general with advantage etlectcd in the presence of basic-reacting substances particular organic bases, such as pyridine and the like.

The process according to this invention enables 1.52,-=i-t1'iazoles to be prepared in good vicld u uereas the known processes for prep: ring triazoles by heating di-acyl hydrazines or mono-acyl hydrazines with acid amides to elevated temperatures (1804300 C.) (ldeyer Jacobson, Lehrbuch der organischen Chemie, 1915/20, vol. 2, part 3, page 592) only give yields of 10-15% of theory. (ct. Chem. Centr. 1001 II, page 124; and Chem. Centr. 1911 11. page 1936.)

The following examples serve to illustrate how the invention may be carried into effect.

1. guns. of methyl acetamide are dissolved in a mixture of 2% grins. of pyridine ant. l0l arms. of chloroform, after which 76.5 grins. of phosphorus oxychloride diluted with T5 guns. of chlorofmim are added drop by drop whilst cooling to about 0 C. After allowing to stand for some time the solution containin the lactim ester is introduced with stirring o a solution of 0S arms. of benzoyl hyorazi -c in 520 grins. of chloroform. After allowing" to stand for some time water is added th solution neutralized and evaporated down, the residue extracted by boiling with chloroform and, after evaporating off the solvent, distilled. The product which consists of 3,4-dimethyl-5-phenyl-1,2,4-triazole is very readily soluble in water. On crystallizing from a mixture of benzene and benzine crystals having a melting point of 137 C. and a boiling point of 251 C. (at

The reaction is prob- 14: mm.) are obtained. ably as follows:

orncomaonwroo13 omc=N-on3 +NH2NHCOCOH5 CH;C:N\N

2. 3 1 grins. of acetophenone oxime mol) and 11 grins. of caustic soda are dissolved in 150 cos. of water and 150 ccs. of chloroform and 4-5 grins. of benzene sulphonic acid chloride mol) introdced drop by drop at 5 C. The mixture is esterified for 1 hour at 2 (1, then acidified and the chloroform solution of the ester separated. 22 grins. of propionyl hydrazine A mol) dissolved in ccs. of chloroform are added to the ester solution and converted at 20-25 C. After neutralizing the chloroform solution, the solution is evaporated down and the residue distilled. A satisfactory yield of 3-1nethyle-phenyl-S-ethyl-lQA-triazole is obtained. The latter comes over at 213-214: C. under 1 mm. pressure, crystallizes from benzenebenzine with a melting point of 152 C. and

readily soluble in Water.

A solution of 61 grms. of thionyl chloride in 7 ccs. of chloroform is added drop by drop with cooling to 0 C. to a solution of 34; gram. of acetophenone oxime in 11115. of chloroform, whereby estcrilication and conversion take place. After standing for a short time the solution is carefully introduced with slight cooling into a solution of 22 grins. of propionyl hydrazine in 150 grins. of chloroform.

Alter the reaction has proceeded for some time the reaction product is decomposed with water and the resulting triazole isolated. 3 methyl l phenyl 5 etliyl-1,2,-l-triazole of melting point 152 (3., which is chemically identical with the product memes obtained according to Example 2, is obtained;

4. 28vgrms. of acetanili'de (0.2 mol) are dissolved in 200 cos. of chloroform and treated whilst cooling with 42 grins. (0.2 mol) of powdered phosphoruspentachloride. The phosphorus pentachloride goes completely into solution without any substantial evolution of hydrochloric acid gas. After about ,4 an hour 18 grins. mol) of'propionyl hydrazine dissolved in 100 ccs. of chloroform are added with slight cooling. This temperature is maintained aborit20 C. AfterstancL ing' for '2 hours the mixture is warmed for a short time to 45 "C. whereupon slight hydrochloric acid gas evolution takes place. In order to destroy the phosphorus oxychloride, water and caustic soda solution are added with cooling until the solution reacts ZL'llUlline to phenol phth-alei'n. The consumption of alkali amounts to about57 grins. of caustic soda solution 100% of theory:

A portion of the reaction product, consisting of hydr'azidine is precipitated from the chloroform solution in the form of thin needles. After careful re-crystallization from alcohol it has a melting point of 152'153 'C., is soluble in water and with diiiiculty soluble in chloroform. 4 On heating to 160 C. the hydrazidine is quantitatively converted into the 3-1nethyl %l-phenyl-5ethyl-1, 2, 4e-t-riazole which boils a't219" "C. under 15 mm. pressure and crystallizes from benZene-benzine with a melting point of 1'52153 C. The reaction CaHaNHCOCH3+PCl5fiCoH5N C-CH3 I A portion of the hydrazidine is already converted during the reaction of the subsequent operations into the tria'zole andremains dis-solved in chloroform. Theyield of pure triazole amounts to 70-80% of theory. The reaction product is identical with that obtained according to Example 2 from acetophenoneoxime. H V

5. 30 grins. of forman'ilido are dissolved in 40 grins. of pyridine and 150 grins. of chicchloride carefully added at to C. After t'he reaction has taken .place for a short time the solution is introduced at 10 '0. into a solution of 19 grins. of acetyl hydrazine and-1'00 cos. of El-1380 111156 alcohol. After the completion of the reactionthe mixture is triaz'ole may be obtained by causing the imido ester of acetanili 'n'e to react with for'm'yl hydrazine. V 1

' 6. 35 grins. of acetooyclohexylamine are dissolved in a mixture of 40 grms. of pyridine 1 and 120 grins. of chlorof-rom and treated at -25 C. with45 grins. o'f'benzenesulphonic chloride. After completion of the conversion the solution containing the imido ester is introduced at -40 G. into a solution of '29 grins. of isovaleryl hydrazine and 150 grins. of chloroform. After the reaction has taken place for some time aqueous alkali is added.

aqueoussolution it is precipitated by the adcii'tion of sodium chloride as which may be recrystallized from ether as crystals have a melting point of'67 O. The

the hydrate,

reaction is as follows:

7. 4O grins. of aceto-maiylidine are dissolved in a inixtnre of 40 grins. of pyridine and 7 5 grins, of chloroform and treated at about 30-40 C. with grins. ofbenzene sulphonic chloride. After completion of the es't-erification the solution is introduced into a solution of 25,5 grins. of isobutyryl hydrazine and 150 grins. of chloroform. The mixture is worked up as described in Example '9. 3 methyl-tniexylyl-5-isopropyl-1,2A-triazole may be obtained from the resulting hydrazidine of-ineltii-ig point 196 C. the elimination of water. The producthas a boiling point of 182 C. and a melting point p or C. and is readily soluble in water. roform and 45 grms. of benzene sulphonic 8. grms. of the p to-luo-l sulphonic acid ester of cycloh'exanone 'oxime are dissolved in 250 ccs. of chlorofor-1n and treated with 33 grin-s. of acetyl hydrazine of theory). The solution is gently warmed up to the conversion temperature of the oxime ester and then cooled to a temperature not exceeding 5 C. The mixture is finally heated until the chloroform boils. The chloroform solution is shaken with potassium carbonate solution in order to remove the toluol sulp'ho-nic acid, "the chloroform solution evaporated and the residue re-crystailized fromwater. 70-80% of theory of 4,5-pentamethylene-S-methyl-1,2,4-triazole is obtained as the hydrate having a melting point of (52 C. The setting point of the anhydrous product is 11l-112 C. and the boiling point 210 C. at 10 mm. This triazole is easily soluble in chloroform and alcohol and also crystallizes very readily from acetic ester and acetone and is with difficulty soluble in ether and petroleum ether. The reaction is:

9. 127 grins. of o-N-methylc-yclohexanone oxime and a l guns. of sodium hydroxide are dissolved in 350 ccs. of water. After adding 100 cos. of benzene 176 grins. of benzene sulphonic chloride are added drop by drop with cooling and vigorous stirring. At the end of the reaction 200 cos. of chloroform are added, the solution of the ester separated from the aqueous liquid and dried under cooling. The ester solution is then introduced at 60-65 C., drop by drop with slow stirring into a solution of 130 grms. of diethyl-acetyl hydrazine and 250 ccs. of chloroform. At the end of the conversion water is added and the solution neutralized with alkali. The chloroform and benzene are removed by evaporation. After cooling the hydrazidine formed separates out from the aqueous solution. It may be purified by dissolving in acid and precipitating with alkali. It crystallizes from alcohol in the form of needles having a melting point of 205 C. The dried hydrazidine is heated in an oil bath to a temperature above its melting point, whereby water is eliminated and the hydrazidine is converted into the diethyl-(1-1.2,at-triazole of the methyl-e-leucine lactam. This triazole boils at 170 C. under 0.5 mm. pressure. From water it crystallizes as the hydrate.

10. 1.6 grms. of benzene sulphonic chloride are slowly added whilst cooling to about 0 C. to a solution of 28.5 grms. of e-lGUClDB lactam in a mixture of L0 grms. of pyridine and 110 grms. of chloroform. After allowing to stand for about an hour at 0 C. the solution of the lactim ester is introduced into a solution of 29 grins. of isovaleryl hydrazine in 150 grins. of chloroform. After decomposing with water and neutralizing, the solution is evaporated down, extracted with chloroform and the chloroform residue distilled. A good yield of 3,1-pentamethylene-5-isobutyl'lfiA-triazole, having a melting point of 50 C. and a boiling point of 183 C. at

0.4 mm., is obtained. The product is very hygroscopic and very readily soluble in water and organic solvents. The react1on 1s:

11. 22.5 grms. of phenyl-benzimido-ethyl ether are mixed with 9 grms. of acetyl hydrazine and heated in an oil bath for several hours to about 150 C. After cooling the solid hard mass is triturated with ether and y then with water, dissolved in dilute acid and the resulting triazole precipitated with alkali. 3, l-diphenyl-5-methyl1QA-triazole is obtained and may be crystallized from a mixture of benzene and benzine as crystals having a melting point of 163 C. The same triazole can also be obtained from the benzene sulphenic acid ester of acetophenone crime by conversion with benzhydrazine as well as from the benzene sulphonic acid ester of benzophenone oxime and acetyl hydrazine by conversion of the oxime ester in the pres ence of the acyl hydrazine.

The term acid halogenides in the s iecification and in the claims is to be understood to include both inorganic acid halogenides, such as phosphorus pentachlori'de, thionyl chloride, and the like, as well as the halogenides of strong organic acids such as benzol or toluol sulphonic chloride and the like. The imido compounds employed starting materials in the process according to this invention are to be understood to include both in the specification and claims also such imido compounds in a non-isolated form,

for example in the form of non-isolated intermediate or unstable intermediate products.

What we claim is 1. A process for preparing 1,2, l-triazoles wherein acyl hydrazines of the type- NH: ILELAc,

where Ac represents an acyl radical are caused to react with imido compounds of the type- R1-CX wherein R and R are each an alkyl or aryl radical. and wherein X is any radical which is capable of mutually reacting with one of the hydrogen atoms of the acyl hydrazines.

2. A process as claimed in claim 1 wherein the acyl hydrazines are caused to react with imido esters of the type characterized in claim 1.

3. A process as claimed in claim 1, wherein the acyl hydrazines are caused to react with the products of the Beckmann transformation of ketoXiInc-s.

4. A process as claimed in claim 1, wherein the acyl hydrazines are caused to react with the products of the Beckmann transformation of sulphonic acid esters of ketoXimes.

5. A process as claimed in claim 1, wherein the acyl hydrazines are caused to react with the reaction products of inorganic acid halogenides with secondary acid amides.

6. A process as claimed in claim 1, wherein the acyl hydrazines are caused to react with the products of the reaction of inorganic acid chlorides With secondary acid amides in the presence of basic substances.

7 A process as claimed in claim 1, wherein the acyl hydrazines are caused to react with the products of the reaction of inorganic acid chlorides with secondary acid amides in the presence of pyridine.

S. A process as claimed in claim 1, wheren the acyl hydrazines are caused to react with the products of the reaction of organic sulphonic acid chlorides with secondary acid amides in the presence of basic substances.

9. A process as claimed in claim 1, wherein the acyl hydrazines are caused to react with the products of the reaction of organic sulphonic acid chlorides with secondary acid amides in the presence of pyridine.

10. A process as claimed in claim 1, where in the acyl hydrazines are caused to react with imido ethers of the type R1-'COR;

,. wherein R R and R are each analkyl or tures.

DR. GEORG SCHEUING. DR. BRUNO WALACH. 

